Zimmerman went 0-for-3 with a sacrifice fly while serving as the designated hitter Friday night.
Washington manager Matt Williams said Zimmerman is close to returning and could play third base, first base and/or left field at Potomac.
Zimmerman was placed on the 15-day disabled list April 13 after breaking his thumb while diving back into second base on a pickoff attempt the day before. He has missed 41 games.
Washington (26-27) had lost six of seven before beating the Texas Rangers 9-2 to open a three-game interleague series on Friday night. The Nationals had scored 19 runs and hit .127 with runners in scoring position during the seven-game stretch.
Zimmerman was hitting .364 with two homers and six RBIs in 10 games before the injury.
The Associated Press contributed to this report.